Accompaniment chord rhythm system



o. A. BUNGER 3,499,092

S Sheets-Sheet 1 ACCOMPANIMENT CHORD RHYTHM SYSTEM i n 2 H 3 fl. mw ER n my 06 1 2 I m q E m m 6 T GL 1 E m n 5 S N F 2 M S 7 "8 F m 8 .7 I. X 0 R 6 l. .2 Ep M mm mm m A} PG PG W 5:

March 3, 1970 Filed Aug. 12, 1968 March 3, 1970 o. A. BUNGER ACCOMPANIMENT CHORD RHYTHM SYSTEM 3 Sheets-Sheet 2 Filed Aug. 12, 1968 o R R E 0. 0H 0 mm m m N m m u n 1 A w m P q I m u. 58.5 82 u v. 5 58 #52. m we \C I. I mu TH uh] I r N 5 q m 1nd in. 2nd w w sm. 7 x! sum 2 H W 5 T .0 T 5 T uv 5 5w Us x2. 12 '5. E. H w .w d -09 Emu F dimvfiw IIQIIIIIIQHIIJ J 8 mm x: mm w s3 o ca m0 2... V Ni March 3, 1970 A. BUN R 3,499,092

ACCOMPANIMENT CHORD RHYTHM SYSTEM Filed Aug. 12, 19 68 3 Sheets-Sheet 3 PEDRL RESET 12 EVERY OTHER BERT \OOK SIGNHL lN 2 I l 9 2 H l -l m INVENTOR kgxag DAVID A. BUNGER E9335 fiAla-ni,

BY M ai -F- M ATTORNEYS United States Patent O Int. Cl. Gf N08 US. Cl. 84-1.03 18 Claims ABSTRACT OF THE DISCLOSURE The playing of chords on an accompaniment manual keyboard of an electronic organ is facilitated by use of a shift register which can be stepped along by the mere repetition of one note of a chord and which can be reset by a flip-flop triggered by alternate keyings of a pedal keyboard. The shift register output may be programmed to actuate normally-off gates to pass signals through tonecolor filters of diverse character to obtain desired rhythm patterns comprised of different voices. A resistive network is provided which advances the shift register for each actuation, whether or not keys are then already actuated.

This application is a continuation-in-part of my application Ser. No. 615,217, filed Feb. 10, 1967, entitled Stepping Rhythm Interpolator, assigned to the same assignee as the present application.

BACKGROUND OF THE INVENTION In recent years there have been known two general types of rhythmic interpolators to provide rhythmic patterns of percussive voices in electronic organs. In one form, a rhythmic sequence of percussive sounds is generated in a controllable tempo. The timing of the individual sounds forming the sequence is not under con tinuous control of the player, as he plays, but the player must follow the tempo of the device, such as exemplified in U.S. patents to Park, Nos. 3,146,290 and 3,255,292.

In another form, a rhythmic pattern is pre-established for each measure of the music (or for each two measures), but each complete pattern is initiated by a signal, i.e., the playing of a note or the closure of a switch. Each time the signal occurs, the same sequence of voices may be heard. Tempo may be manually established or may be automatically computed from the time separation of the signals. This type of device is exemplified in US. patents to Campbell, Nos. 3,140,336 and 3,247,309.

In addition to the above, the present inventor discloses in a co-pending application, Ser. No. 615,217, filed Feb. 10, 1967, a stepping rhythm interpolator in which a shift register is employed to call forth percussive sounds in a predetermined sequence. No sound occurs until the player keys a particular key in a keyboard, say an accompaniment manual. The playing of a note steps along the register to the next stage, which may call forth a percussive sound different from the preceding one. The resetting of the register to restart a desired sequence may be accomplished by keying a pedal keyboard.

According to the present invention, the. principal object of which is to produce a rhythmic sequence of chords in an electronic organ in diverse voices, a shift register is used to actuate gates in series with various tone-color filters so as to make the gates operative to pass the signals corresponding to the desired sequence of voices. Another object is to make it possible for a player to repeat a chord, played say with three fingers, by the mere lifting and redepressing of a single key corresponding to one note in the chord.

Parallel-connected auxiliary key switches, operated concurrently with tone-signal key switches in an accompaniment keyboard, pass direct current to activate a trigger amplifier whose output triggers a shift register from one stage to the next, each stage being operative to actuate a tone-signal gate in series with a tone-color filter to provide a rhythm pattern of diverse voices. Signal keyed by pedal key switches activates a trigger amplifier to trigger a flip-flop connected to the shift register, so that alternate keyings of the pedal keyboard reset the shift register.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a part-schematic, part-block diagram of an embodiment of this invention;

FIGURE 2 is a similar type diagram of a variation of a portion of the diagram of FIGURE 1;

FIGURE 3 is a schematic diagram of a shift register and accompaniment trigger amplifier for use with the invention;

FIGURE 4 is a schematic diagram of a trigger amplifier and flip-flop for use with the invention; and

FIGURE 5 is a schematic diagram of a gate for use with this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIGURE 1, tone-signal sources 10, 12, 14 represent three of a gamut of sources corresponding to notes of a musical scale and may, for example, each comprise a stage in a chain of continuously-running (during operation) frequency-dividing flip-flops as known in the art. Respectively connected in series with sources 10, 12, 14 are decoupling resistors 16, 18, 20 and key switches 22, 24, 26, operable by the respective keys (not shown) of, for example, an accompaniment keyboard 28. The resistors 16, 18, 20 have a common connection in a collector 30, which, in turn, has connections to a pair of normally-off percussive-type gates 32 and 34, to be described in detail with reference to FIGURE 5. Tone-color filters 36 and 38 are shown in series with gates 32 and 34, respectively, and with a common connection to a stop-tab switch 40 in series with the usual amplifier 44 and loud speakers 46.

Ganged respectively to the key switches 22, 24, 26, are auxiliary key switches '48, 50, 52 having a common connection 53 to a source of negative potential V The switches 48, 50, 52 are in series with resistors 54, 56, 58 which have a common connection to a trigger amplifier 60, the output of which is connected to a shift register 62, these latter two components being illustrated in detail in FIGURE 3. The shift register 62 has four outputs 1, 2, 3 and 4, having connections respectively to four steering diodes 64, 66, 68 and 70. An exemplary connection of the diodes is illustrated in FIGURE 1, with diodes 64, 66 and 68 coupled to gate 32 and with diode 70 coupled to gate 34. The shift register 62 has also a reset input derived from a flip-flop 76, which is in series with a trigger amplifier 78, which is connected to negative source V via a series resistor 79. Also connected to resistor 79 are switches 80, 82 which are actuable by pedals (not shown) of a pedal keyboard 84. In series with the switches 80, 82 are respective resistors 81, 82 and respective percussion or sustain gates 85,87 ,with shunt capacitors 89, 81 connected as shown.

In the operation of the system of FIGURE 1, assume that accompaniment key switches 22, 48, and 26, 52 are closed together, as they might be in playing a chord having two notes a whole tone apart in the equally-tempered Patented Mar. 3, 1970 I scale. Also, assume that the shift register 62 is in such a state as to render output 1 effective. At the instant of switch closure, tone signals from sources and 14 pass through key switches 22 and 26, respectively, to collector 30, from which they are transmitted to the signal input of both gates 32 and 34. Since the gates are normally off, no signal will pass through. However, at the same instant, DC. from source V will pass through switches 48 and 52 to the trigger amplifier 60. A pulse from the latter will enter the shift register 62 and cause a positive output at 1. The diode 64 passes the pulse, thereby pulsing the gate 32 and turning it on. Then the signals from sources 10 and 14 will pass through the gate 32, be modified in harmonic content by the filter 36, be amplified by amplifier 44 (if the tab switch 40 is closed) and converted to sound in the speaker 46. Since the gate is of the percussive type, the signal rises abruptly to a maximum and decays gradually depending upon the time constant of the gate circuit.

Assume now that the switches 22, 48, and 26, 52 remain closed, as would be the case if the chord were held. Then if one finger were lifted for a short period, say one second, and then pressed back down on the key operating the switches 22, 48, signal from the source 10 would again be present at both gates 32 and 34 along with the signal from source 14, the switches 26, 52 for which hav ing remained closed. At the same time, D.C. would pass through switch 48 causing another pulse at the input of the register 62. This time the output 2 would be effective to pass a pulse through diode 66 to reactuate the gate 32 to pass another percussive sound at the pitches of both sources 10 and 14 and of a tone color determined by the filter 36. In like manner, if the same finger were lifted again and then pressed back on the key operating switches 22, 48, percussive signals would again be heard corresponding to sources 10 and 14, having been gated by a pulse through diode 68 from output 3 of the register 62. However, another lifting and depression of the same key would cause a pulse to pass from output 4 through diode 70 and on to gate 34, which would pass percussive signals at the same pitches (from sources 10 and 14), but of a tone color determined by the filter 38. Thus there would be a sequence of three successive percussive chords of one tone color followed by one chord of another tone color.

The utility of the system may readily be seen, because the outputs 1, 2, 3 and 4 may be connected in any one of a large number of combinations to one or both of the gates 32 and 34, as well as to additional gates (not shown) connected to other tone-color filters (not shown). For example, in FIGURE 2, the outputs 1, 2, 3 and 4 are connected so that gate 32 is actuated first, then 34, then 32 and 34 together (by means of an additional diode 86), then gate 34 alone for a corresponding rhythmic sequence of the same chord, with varying tone colors.

Even if the same or another chord is played following the above described sequence, the shift register will revert to a condition wherein output 1 is effective. However, it is highly desirable to have the arrangement of the upper portion of FIGURE 1, whereby playing of a pedal key will act to reset the shift register 62 on the second closure thereof. This is accomplished by closure of a pedal key switch, such as 80, which pulses the trigger amplifier 78 (by virtue of the passage of DC. from V to capacitor 89 via resistor 81 and gate 85), thereby rendering the fiip-fiop 76 effective upon a second closure to reset the register 62. This way, in 4/ 4 time, for instance, if a pedal were played on the third beat, it would not reset the register, thus allowing a full sequence of four rhythmic chords to be played. It will be obvious to one skilled in the art that not only can additional voices be made effective with additipnal gates and filters, but also larger shift registers with additional gutputs may be employed, thus making available almost limitless rhythmic patterns, as des r d.

In FIGURE 3 is provided a schematic diagram of a shift register and accompaniment trigger amplifier, which may be used in the system of FIGURE 1. Each of the stages 1, 2, 3' and 4 include a single transistor, these being identified as T1, T2, T3, T4. The emitters of the transistors T1T4 are grounded and the collectors are connected to a +10 v. bus (via respective load resistors 88), which derives its voltage from a 22 v. bus 92 via a voltage dropping resistor 93. It is assumed that each ofthe transistors at T1T3 is saturated, at 4.5 ma. but that transistor T4 is unsaturated.

Transfer pulses for the shift register are present at point 94,'having been derived from the output of the accompaniment trigger amplifier 60 (comprising transistors T5 and T6 and associated components), at the input point 96 of which are applied D.C. pulses derived from the key switches 48, 50, 52 of FIGURE 1. A negative transfer pulse at 94 has no effect on the saturated transistors Tl-T3, but the negative trigger applied to unsaturated transistor T4 via its collector resistor is also applied via load 98 to the base of transistor T1, driving T1 out of saturation. This raises the voltage at the collector of T1, and that rise is transferred to the base of transistors T3 and T4 via lead 100 and to the base of T2 via the capacitor 102 and resistors 104 and 106. Thus T2 and T3 remain in saturation. T4 becomes saturated and T1 is now unsaturated. Succeeding trigger pulses step the shift register along in like manner.

A negative-going reset pulse is applied directly to the base .of transistor T1, from terminal 108 (see also FIG- URE 1) on alternate pedal key depressions, provided pedal reset is utilized in the system. To provide pedal reset, resort is had to the system of FIGURE 4 of the accompanying drawings.

In FIGURE 4, positive pulses produced by pedal actuation are applied to the terminal 110 via trigger amplifier 78 (see also FIGURE 1), which is coupled directly to the base of transistor T7.

The collector of transistor T7 is coupled via capacitor 112 to a flip-flop 76, comprising cross-coupled transistors T8 and T9 and their associated components. The flip-flop 76 provides an output pulse from the collector of T9 only on each second pulse applied to the flip-flop, which acts as a divide-by-two circuit. The output of T9 is a negative-going pulse, applied to pedal reset terminal 108 via diode 116.

In general, any type of register may be employed in the practice of the invention, including a mechanical stepping switch.

An exemplary gate for use with the system of FIG- URE 1 is illustrated in FIGURE 5, wherein transistors T10 and T11 and their associated components comprise a switch for the positive pulse applied at the terminal 118 from one of the outputs of the shift register 62 of FIGURE 1. The FET 120 serves as the gating element in the signal circuit, its drain terminal D having a connection with the collector 30 (of FIGURE 1), and its source terminal S being connected to one of the tone-color filters 36, 38. The FET 120 is normally biased into nonconduction by a negative potential at its gate terminal G by the voltage on the capacitor C, which has been charged through resistor R by the voltage divider connected to a source of potential V The transistor T11 is normally off. The diode 124 is shown connected between the collector of T11 and G of FET 120 and is normally reverse biased.

In operation, a positive pulse applied at terminal 118 drives T10 and T11 into saturation, forcing their collectors to ground potential. The negative charge on the capacitor C quickly passes via the diode 124 and transistor T11 to ground thus carrying terminal G to ground and causing FET 120 to allow the signal 126 to pass through it quickly. However, upon cessation of the pulse at 118, T10 and T11 turn off, diode 124 stops conducting and ca-. pa o C cha g s p g n f om V. drivi g ET 120 5. into non-conduction at a rate determined by the time constant of R and C. Thus, a percussive-type envelope 128 (having quick rise time and gradual decay) is imparted to the signal input 12'6.

What is claimed is:

1. In an electronic organ having a plurality of tonesignal sources corresponding to notes of a musical scale, a plurality of keying means respectively. coupled to said sources, and at least two tone-color filters of diverse characteristics coupled to an output system, the combination comprising at least two percussive gates coupled between said keying means and respective ones of said tone-color filters,

a shift register having plural stages,

means responsive to actuation of any one of said keying means for generating a control pulse,

means applying said control pulses to advance said shift register for providing a further control pulse on each advance, and i 7 means coupling said plural stages, selectively with said percussive gatesfor selective actuation of said percussive gates by said further control pulses-to: render said percussive gates selectively conductive.

2. The combination according to claim 1, including pedal keying means, and

means coupled to said pedal keying means and responsive to operation thereof for resetting said shift register.

3. The combination according to claim 2, wherein said last-mentioned means includes a flip-flop coupled to said shift register in such mode that alternate actuations of said pedal keying means reset said shift register. a i 4 4. In an electronic organ having a plurality of tonesignal sources corresponding to notes of a musical scale, a plurality of key switches respectively coupled to said sources to call forth tone-signal and at least two tonecolor filters of diverse characteristics coupled to an output system, the combination comprising:

at least two percussive gates coupled between said key switches and respective ones of said tone-color filters,

an electronic shift register having plural stages,

a direct current source,

a second plurality of key switches concurrently actuable one for one with said first plurality of key switches,

a trigger amplifier coupled to said shift register,

means including said second plurality of key switches connected in parallel between said direct current source and said trigger amplifier for initiating control pulses to advance said shift register for providing a further control pulse on each advance, and

means coupling said stages respectively with said gates for selective actuation thereof by said further control pulses.

5. The combination according to claim 4, including pedal key switches, and

means coupled to said pedal key switches and responsive thereto for resetting said shift register.

6. The combination according to claim 5, wherein said last-mentioned means includes a flip-flop coupled to said shift register, whereby alternate actuations of said pedal key switches reset said shift register.

7. -A rhythm system comprising in combination:

an electronic organ having a key-board,

a plurality of tone-signal sources,

a shift register having plural stages,

means responsive to actuation of keys of at least a portion of said keyboard for generating a control pulse,

means applying said control pulses to advance said 6 shift register for providing a further control pulse on each advance,

at least two tone-color filters of diverse character,

at least two percussive gates respectively coupling said sources with said filters,

means for selectively actuating said gates in response to said further control pulses, and

electroacoustic translating means coupled to said tonecolor filters.

8. In an electronic organ having a plurality of tone sources corresponding to notes of a musical scale,

a plurality of switch means respectively connected in cascade with said sources,

means including a resistive network for generating a control pulse in response to each actuation of one of said keys regardless of whether or not others of said keys are concurrently in actuated condition,

a shift register having plural stages,

means responsive to each of said control pulses for advancing said shift register by one stage,

an output circuit for said organ,

at least one percussive gate interposed between said tone sources and said output circuit, and

means responsive to advances of said shift register for rendering said at least one percussive gate conductive.

9. The combination according to claim 8, wherein said at least one percussive gate is a plurality of percussive gates connected in parallel, and

wherein said means responsive to said advances of said shift register is means for selectively rendering said percussive gates conductive as a function of the specific advances achieved by said shift register.

10. The combination according to claim 8, wherein said means including a resistive network includes,

a DC. voltage source,

a secondary switch operative with each switch of said switch means,

a relatively high resistance connected in cascade with each of said secondary switches,

a relatively low resistance summing resistance connected commonly in series with all said relatively high resistance switches, and

means connecting said secondary switches in said resistive network arranged to produce one of said control pulses across said relatively low resistance in response to each closure of at least one of said secondary switches.

11. In an electronic instrument for generating repetitive rhythm patterns,

a multi-stage shift register,

a plurality of keys,

means responsive to actuation of one or more of said keys regardless of whether or not one or more others of said keys are then in actuated condition for generating a control pulse,

means responsive to each of said control pulses for advagcing said shift register from one stage to another, an

means responsive to each advance of said'shift register from one stage to another for generating an audio tone.

12. The combination according to claim 11, wherein said last means includes a means for determining the tonal character of said audio tone as a function of the totality of keys actuated at the time of said advance.

13. The combination according ot claim 12, wherein is provided plural audio tone channels, and wherein is provided means for programming said plural audio tone channels to pass said audio tones according to the state of advance of said shift register.

14. The combination according to claim 13, wherein said plural audio tone channels include at least two audio channels having respectively diiferent tone-color filters capable of imparting respectively diverse tone colors to the output of said organ.

15. In an electronic organ,

a plurality of keys, each having an actuated and an unactuated condition,

a plurality of continuously operative tone-color sources,

a plurality of tone-color filters,

an audio output system connected in cascade with said plurality of tone-color filters,

means responsive to each actuation of one of said keys irrespective of the then condition of others of said keys for percussively transmitting tone from said tone sources to said audio output system selectively via at least one of said tone-color filters, and

means for programming operation of said the last named means in a sequence established by actuation of said keys.

16. In an electric organ,

a plurality of tone-signal sources arranged according to a musical scale,

a plurality of percussive gates connected in parallel to said tone-signal sources,

a separate tone-color filter in cascade with each of said percussive gates,

an audio output system connected in cascade with all said gates,

an array of keys actuable to call forth tone signals, and

means responsive to successive actuation of a key irrespective of Whether others of said keys are then in actuated condition for rendering said percussive gates conductive in a predetermined sequence.

17. The combination according to claim 16, wherein is provided a further array of actuable keys, and

means responsive to actuations of any of said further array of actuable keys for initiating said predetermined sequences 18. A percussive gate foran electrical signal representing a sound of a musical instrument, comprising:

a PET having a signal input electrode, a signal output electrode and a gate electrode,

a pulse forming network connected to said gate electrode,

a source of said electrical signal connected to said signal input electrode to apply said electrical signal thereto,

a load connected to said signal output electrode, said pulse forming electrode including a capacitor connected between said gate electrode and ground,

means including a source of negative bias voltage connected to said capacitor and normally maintaining said capacitor negatively charged to maintain said FET non-conductive,

a diode having its cathodevconnected to said gate electrode,

means including a source of diode blocking voltage connected to said diode for preventing current flow therethrough,

means for transiently grounding said diode, and

a relatively high resistance connected between said source of negative bias voltage and said gate electrode, the values of said capacitor and said relatively high resistance being arranged to provide an audibly long charge time of said capacitor following its transient discharge.

References Cited UNITED STATES PATENTS 3,147,333 9/1964 Wayne 84l.24 3,217,081 11/1965 Nakada 84--l.19 3,235,648 2/1966 George 84-103 3,317,649 5/1967 Hearne 841.17 X 3,359,358 12/1967 Brand et al.

HERMAN KARL SAALBACH, Primary Examiner T. VEZEAU, Assistant Examiner U.S. Cl. X.R. 84--l.08, 1.24 

